Question

The area of an isosceles triangle having base 2 cm and the length of one of the equal sides 4 cm, is ______.

विकल्प

• `sqrt(15)` cm² 

• `sqrt(15/2)` cm²

• `2sqrt(15)` cm²

• `4sqrt(15)` cm²

Answer 1

The area of an isosceles triangle having base 2 cm and the length of one of the equal sides 4 cm, is `underlinebb(sqrt(15)  cm^2)`.

Explanation: 

a = 2, b = 4, c = 4

`s = (a + b + c)/2`

⇒ `s = (2 + 4 + 4)/2 = 10/2 = 5`

Area (Δ) = `sqrt(s(s - a)(s - b)(s - c))`

⇒ Area (Δ) = `sqrt(5(5 - 2)(5 - 4)(5 - 4))`

⇒ Area (Δ) = `sqrt(5 xx 3 xx 1 xx 1`

⇒ Area (Δ) = `sqrt(15)` cm²